A hybrid vehicle having both an internal combustion engine and an electromotor exists nowadays. The internal combustion engine provides mechanical energy by combusting fuel such as gasoline, and the mechanical energy can be used directly for driving a vehicle and can also be converted into electric energy by an electric generator for driving a vehicle or charging a power battery. The electromotor can drive the vehicle by means of the electric energy provided by the power battery or the generator. As for the hybrid vehicle, the engine can run constantly in a highest efficiency under an optimal control thereof, thereby achieving low pollution and energy conservation.
An air-conditioning system of a vehicle can regulate the air temperature in the cabin, and has an important influence on driving experience such as body comfort and the like. The air-conditioning system generally can include a refrigerating part and a heating part.
In one heating mode, the hybrid vehicle adopts a water heating device which heats air with waste heat generated when the engine of the vehicle runs. Thus, usually a heater core for heat exchange is arranged in a cooling water circulating loop of the engine to heat the air to be delivered to the cabin. In another heating mode, an electric heating device is utilized to generate heat and heat air with electric energy. As for the vehicle adopting the water heating device, especially under the condition of cold start of the vehicle, the cooling water can rise to an appropriate working temperature only after the engine runs for a long time, and passengers may stand bad experience caused by cold within this period of time. As for the vehicle adopting the electric heating device, a high-power electric heater of about 2 kw, such as a PTC heater, is usually adopted in order to achieve the warming effect required by the passengers. This electric heater can quickly heat air, but will seriously influence the endurance mileage of the whole vehicle after long-time working. In addition, the high-power electric heater consumes electricity too fast and easily leads to deep electricity loss of the power battery, so that the service life of the power battery is shortened.
The refrigerating part in the air-conditioning system generally adopts a mechanical compressor which is driven directly by the engine of the vehicle. However, the engine of the hybrid vehicle is not always in a working state. For example, for a series strong hybrid vehicle, the engine is started only when the SOC value of the power battery reaches a low threshold or when the engine needs to be forcedly started due to the power demand. For a medium or weak hybrid vehicle, an automatic stop or idle stop mode is usually set for the engine in order to save energy. In the automatic stop mode, when the vehicle is idle, the engine can automatically stop and can be automatically started after a certain time. It can realize combustion economization of the engine, but it is adverse for the operation of the compressor driven by the engine. It is possible that when the compressor needs to work, the engine serving as a driving source of the compressor does not work. Thus, in one existing solution, the engine is forced to work when the compressor needs to run. However, under some situations, particularly during the vehicle is parked, the engine works only for driving the compressor, which obviously increases the energy consumption uneconomically. In another solution, an electrically-driven or electrically/mechanically-driven compressor is provided, but the cost of the compressor is significantly higher than that of a conventional mechanical compressor.
Moreover, the present applicant proposed a power system of a series hybrid vehicle in Chinese Patent Application No. 201310467918.2, the entire contents of which are herein incorporated by reference. It will be discovered below that the present invention can achieve unexpected technical effects based on the power system of the series hybrid vehicle in the cited application.